This application relates to and is a further improvement of my U.S. Pat. No. 3,885,771, in that it provides for manual or piston operated shut-off valves of the eccentric rotary disk type used for tight shut-off purposes as demanded by piping systems handling gaseous or liquid media.
My previous invention, more suitable for automatic control purposes, featured an eccentrically mounted plug, co-operating with a rigid metal seal which did not provide the degree of leak tightness demanded by on-off valves.
The present invention provides for a unique combination of a fluid pressure actuated seal made from a relatively flexible material such as a high strength nickel alloy, with the eccentrically adjustable seat ring, featured in the above referenced patent, to add perfect geometric alignment towards the rotating disk thereby assuring repeatable tight shut-off regardless of flow direction.
A further objection of this invention is the employment of an eccentric disk of well known prior art for compact construction and low mass. However, contrary to prior art, sealing between the spherical disk periphery and the seat ring is greatly simplified in that the controlling distance between disk and seat ring is no longer dependent upon very tight machining tolerances within the valve body, but can be adjusted very simply during the final assembly stage by rotating the eccentric seat ring around the periphery of the disk until both axis are properly aligned.
In the prior are U.S. Pat. No. 4,058,290, showing a disk co-operating with a metallic packing or seal ring, alignment is accomplished via radial displacement of the seal ring by the disk. The disadvantage here is the difficult-to-machine shape of the disk and the requirement for the seal ring to form a movable seal not only against the disk, but also against the housing itself. My invention does not have these disadvantages.
Yet another objection of my invention is the provision of a rotating disk having greatly reduced hydro-dynamic torque values.
Finally, my invention utilizes a centrally open hub section around the shaft not only to facilitate the machining operation of the disk, but also to increase the available flow area and thereby improve the flow capacity of my invention over similar valves of established art.